Galena with Sphalerite

Unknown Owner

Superb example for the species from this locality, a grouping of lustrous galena crystals, these hosting slightly translucent deep red to black crystals of sphalerite. Collected in the 1980s, in excellent condition.The Denton Mine, located in the Cave-in-Rock District of Hardin County, Illinois, is a premier locality within the Illinois-Kentucky Fluorspar District. Geologically, it is a Mississippi Valley-Type (MVT) deposit hosted within Mississippian-aged limestones, specifically the Ste. Genevieve and St. Louis formations. The mineralization occurred when fluorine-rich hydrothermal fluids moved through the regional fault systems, creating large solution cavities. Historically, the mine was operated by the Ozark-Mahoning Company and began production in the late 1970s, quickly becoming one of the most significant producers of acid-grade fluorspar in the United States. It remained a vital industrial site until the mid-1990s, when the decline of the domestic fluorspar industry led to the permanent cessation of mining operations in the district.